Piston ring



Patented June 27, 1933 ,UNITED s "m'n-:s

M'rEN'l'sg .OFFICE CHARLES A. mum, or sT. Louis, urssounr, AssIeNoa T neuem nccnssoms mNUFACTUnINe ConroneTIoN, or sT. Louis, MISSOURI; A` CORPORATION or `Application. med' June 27,

y invention has relation to improve.

vments in piston rings for internal combustion engines and it consistsin the novel features of construction more fully set forth in the specication and pointed out in the claim. Briefly, the invention is directed to a one piece ring known in the trade as a snap ring because of the inherent tension in the ring tor holding it in. intimate contact with the cylinder wall. The amount ci tension required to, give satisfactory ring performance in automobile engines as formerly designed is no longer' sucient in the high speed enginesA oi today. Ring manufacturers have sought to keep 'step with the engine manu- `lecturers by loading the rings with tension. ,'lhat is, steadily increasing the ring tension to satisfy the increased demands on the ring, so that snap' rings new have sacien't tension to hear against the cylinder Well with approximately twice the pressure than formerly. Y A

The e'ciency oi a piston ring in holding compression and preventing oil leakage past the piston is dependent on the unit preseine with which the Working face hears against I the ring andthe speed with which the ring responds to irregularities in the cylinder well. Therefore, many ring menuiacturers have decreased the area oi the ring Working tace hy narrowing the ring and toy providing channels in the ring tace. l reduction in the cross-section et' the ring in this manner also increasesits dexihility, which, together with an increase inthe ring tension enables the ring to respond rapidly to cylinder Wall variations andV give eiicient operation,

l-lowever, the reduction in the amount of ring surface contacting with the cylinder Wall naturally increases the amount ot weer on this contacting surface and, although the ring will weer in quickly, its ecient life is greatly shortened. A contributing cause tothe shortened life of a :ring having its working face thus reduced, is the fact that `the ring does not bear against the cylinder wallvith equal preure throughout its entire circumference. 'A one-piece ring `when operating in a cylinder may have a be 'ring pressureoi 10 lbs. across its diameter at right PISTON RING 1931. Serial No. 547,224.

angles to the diameter through the gap, and only 2 lbs. pressure across the gap diameter. This isso because the center of expansion of the ring is opposite to the gap, and the pressure of the surface of the ring at points 90 from the gap is exerted 'perpendicularly against the cylinder Wall. Hence the entire ring tension is exerted against the cylinder Wall at these points, While only a part of the ring tension is exerted at intermediate points. After the ring has 'become only slightly Worn adjacent to the gap, the ends oi the ring will exert practically no pressure on the cylinder Wall and the point diametrically opposite to the gap will exert very little pressure. 0h-

viously, this unequal `pressure at di'erent frs opposite sides of the ring face 99 rorn the gap as illustrated in zlig. 6.

lin order to reduce this rapid weer and resulting decrease in the life of the ring l have provided a ring with a greater amount ci Working surface at the points sulogected to the greatest pressure so that the Wear will he err-inlined around the entire circumference ci the ring.. ln fact., the working surface ci the ring is suhstantially proportional in extent to the pressure ci the ring against the cylinder vvall throughout the circumference of the ring. This will he more readily apparent from the detailed description oi.e the ring which is to follow. a

Another object 'ci the invention is to p ro vide on the face of the ring oil scraping edges that'are inclined respect to the cylinder Wall instead of rectilinear as heretofore, so that these edges will exert e shearing odset onthe oil film on the cyhnderw. rlhis will also appear more clearly from the detail description of the invention 1n connec tion with the accompanying drawmg,`1n whichz. d

Figure 1 is a side elevation of my improved piston ring shown in place in a ring groove in a piston; Fig. 2 is a cross-section through the piston taken on the line 2-2 of Fig. 1,

the piston ring being shown in edge view;

Fig. 3 is a side elevation of the piston ring 4taken at right angles to the elevation shown in Fig.- 1; Figs. 4 and 5 are enlarged crosssectional details taken on the lines 4-4 and 5 5 of Fig. 2; and Fig. 6 is a diagrammatic in the present instance) being cut to form al step joint. However, any common type of joint, such as the lain butt, or bevel may be used. As hereto? is provided with inherent tension so it will expand against the wall of the cylinder C;

in order to adapt the ring for use in high speed engines, the amount of working sunface is reduced by the provision of channels 4, 4, 4 in the ring face 3. As explained above, the reduction of the extent of working 0 surface enables the ring to wear in more quickly than otherwise, and the channels also reduce the cross-sectional area of the ring and increase its flexibility.

It will be observed that the channel 4 ex' tends approximately over one-half the face of the ring and Ais in the shape of an elongated rhomboid, the acute angles 5, 5 of which are rounded and are slightly less than 180 apart. The short diagonal across the ob. tuse angles 6, 6 of the rhomboid shaped channel 4 is diametrically opposite 'to'the gap s of the ring. Thus, the sides 7, 7 of the channel are'inclinedgwith respect to the axis of travel wof the ring. At the same time, the A working face of the ring is greatly reduced ore pointed out, the ring` It has been shown above that the ring bears with the greatest ressure against the cylinder wall across its lar` to the gap diameter so that the reatest amount of wear is on this part of t e ring face. It is to compensate for this greater amount of wear that I have shaped the chan-v nels 4 and 4 as above described so as to provide greater amount of ring wearin surface at these points of greatest wear. he wear on the working face of the ring gradually decreases around the circumference to the ring gap and directly opposite the ring gap and the extent of worklng surface around the circumference of the ring decrease proportionately to this decrease 1n wear.

The edges of the walls 7, 7 of the channels serve to scrape excess oil from the surface of the cylinder wall during the travel of the ring over the wall and since these edges are inclined slightly with respect to the direction of travel of the ring, they will operate more eiliciently owing to their shearing action than would a scraping ed e that is perpendicular to the direction 0% travel. The oil that ameter perpendicuis removed from the cylinder wall by the Y,

CHARLES A; MARIEN.

signature.

A in thickness directly opposite the gap s from which point it gradually widens till the working face is widest at the vertices ofthe angles 5, 5. Extending from each end 2 of 5 the ring through an'angle slightly less than 90 are the triangular channels 4', 4', the widest portion of the channels being of the vsame width as the widest portion of channel i 4, and the channels 4', 4 being narrowest at 55 the vertices of the acute angles 5i opposed to the' angles l5. It will be observed that the channels 4 and 4', 4- are spaced a slight distance. from each other so that; the working surface of the ring extends cle'ar across the w face of the ring along opposite lines 90rom the ring gap. Obviously, the channels 4', 4 may extend across the gap .s instead of terminatmg just short of said gap. Thus, when the gap is closed the channels 4', 4' would 05 connect to form a continuous channel. 

